What Leonardo da Vinci weapon concept used 33 small-caliber guns arranged in rows?

Leonardo da Vinci’s 33-barreled organ was a weapon concept using 33 small-caliber guns arranged in rows.

The design appears in Leonardo’s studies of military machinery. Its nickname comes from the visual resemblance between the grouped gun barrels and the pipes of a musical organ. The barrels were arranged in three rows, allowing one row to be fired while another was prepared or cooled.

This arrangement addressed a major problem with early gunpowder weapons: slow reloading. A crew could potentially fire successive rows rather than waiting for one barrel to be reloaded after every shot. The design was therefore intended to increase the rate of fire.

The weapon is sometimes confused with a modern machine gun. It was not a single automatic firearm, and it depended on manually loaded gunpowder weapons. Like many of Leonardo’s military drawings, it is best understood as an engineering proposal rather than a documented battlefield weapon.